If you watch The Westminster Chorus doing Mardi Gras Parade, there’s a bit near the beginning where the chorus sings, without stopping, moving through different chords, for thirty seconds. I know Farinelli could hold a note for over a minute, but he wasn’t leaping around waving flags and doing somersaults at the same time. Golly.

Of course, now I know that this is mostly smoke and mirrors. You take a breath when you need one. As long as it’s not where Sally says ‘Absolutely NOBODY can take a breath there’, and as long as the other basses don’t all take a breath at the same time, and as long as you don’t LOOK like you’re taking a breath, and as long as we can’t hear you come back in with the note, it’s fine. So I’ve got this figured out, now. Mostly. Breathing while doing choreo has required a few adjustments so I don’t go cross-eyed and faint, but I’m getting there.

It’s the normal, day-to-day, in-and-out type of breathing that’s become problematic. Between hands and feet, I’ve now got enough digits to count the days until Convention. There are even a few left over. Predictably, this is resulting in hyperventilation and the occasional coughing fit.

So for now, my toes are staying firmly in my socks. I’ve got my boots on, too. And my gloves. It’s not that I’m in denial or anything. It’s just that there’s such a lot to worry about.

Seasoned chorus members are telling me I will be terrific, and I mustn’t let the doubt in. As someone who normally approaches challenges with the conviction that everything is bound to go horribly wrong, I have trouble with Positive Thinking. Motivational slogans leave me cold. If people tell me I am fabulous, I laugh and assume they’ve got me mixed up with someone else.

So, as per Sally’s inestimable wisdom, I’m approaching the whole thing like eating an elephant: a bit at a time. Last week, I thought about stage makeup (well, Liz and I drank a fair amount of wine and admired each other’s brushes and decided we needed to wear our fake lashes to rehearsal, just to make sure we could still see Sally from behind them). Today, I’m mostly worrying about vowels, and grins. Tomorrow, I’ll be practising walking backwards in heels.

Sometimes, the stars align themselves just so, and I manage to think about more than one thing at once. At the last rehearsal, I remembered to do something with my face AND my body at the same time. Then Sally gave us some singing points, and it all went to pot again. The tears came, right there on the risers, because I love this so much, and I love the people so much; I can’t bear the thought of letting everyone down.

The chorus, in their usual fashion, are rallying round, giving me bear hugs and tissues, and writing me detailed descriptions of EXACTLY what will happen in the performance, and sharing their mental-pretzel tips on how to turn the terror into a productive force. They say no-one in the little audiences we’ve sung to can tell who the newbies are. I try to believe. I practise beaming at myself in the mirror, telling myself: You’ve worked for this. You deserve to be here. It will be amazing, and you’ll be a part of it.

Eventually, I just decide that it’s easier if I pretend to be someone else. Someone brimming with confidence, skill and natural awesomeness. I visualise the curtains opening to bright lights and two thousand people’s applause. And I channel Beyoncé.

The White Rosettes, not content with being utterly marvellous musicians and the loveliest people on the planet, are also pretty nippy on their feet. My friend Sarah: “I can’t believe you have to do all those MOVES as well as singing!” Me: “Not moves. CHOREO.”

Choreography is VERY important for barbershop choruses. The 220-page Barbershop Harmony Society Contest And Judging Handbook defines Presentation as ‘communication via the transformation of a song into an entertaining experience for an audience.’ The judging criteria talk about ‘believability’ and singing ‘from the heart’ and creating ‘rapport with the audience’. (You aren’t actually allowed to look at the audience most of the time – glancing away from the director is called ‘eyeballing’ and is a Distraction for the judges, which loses you points.) You create this connection with your audience by a) picking a song you can sing well b) singing it well and c) using your faces and bodies to reinforce and amplify the emotions of the song.

Some songs need delicate handling. You really can bring people to tears by standing and singing, not just beautifully, but like you mean it. But others cry out for a bit of The Treatment. Done well, choreography turns a good performance into a showstopper. Here the Rosettes are, doing Cruella De Vil:

It’s the kind of thing that makes sane people suddenly remember an urgent appointment at the other end of the country. Something about being on the risers warps your judgement, though. Perhaps it’s the altitude. You find yourself going, “Cartwheels? Of course. And I can hide those rabbits up my jumper, no bother.”

It’s the end of August. LABBS Convention, the big competition for British ladies’ barbershop choruses, is a suddenly-very-countable eight weeks away. The songs I was struggling to learn a few weeks ago are now embedded in my brain. I know my bums from my dums, and my oohs from my ohs. In fact, it’s all so automatised that Sally can sing any bit of the lead line and I can come in with the bass, without even thinking. This would be kind of impressive, if I didn’t have so much else to worry about. You know the rubbing-your-stomach-and-patting-your-head thing? Try rubbing your stomach and patting your head while reciting key quotations from Hamlet, converting cake mix ingredients for an 8” round tin into a 9” square one in your head, and doing the Charleston. Backwards. In heels. Ginger Rogers, you didn’t know the half of it.

There’s a palpable sense of ‘Right, then!’ in the air. As someone with a background in dodgy amateur dramatics and terrible orchestral playing, I’ve done a fair bit of rehearsing in my time, but I’ve never experienced anything LIKE the pace and intensity of these White Rosettes rehearsals. It’s terrifying and exhilarating and completely exhausting.

Even with seventy-something of us on the risers, there’s nowhere to hide. Sally sees everything. She throws out little reminders to people between takes: “Hands lower down. Right, not left. It’s up in the air, not in front of your face.” Predictably, she catches my eye just as I smack Hannah round the chops. Damn. Damn. Sally: “Welcome back, everyone who’s been on holiday. I Hope You’ve Had A Nice Time.” She’s kind of joking. We laugh, shiftily. It’s not just me looking a bit scared.

Jane’s answering questions. “The first time, the arm goes down behind the person in front of you. The next time, it goes between the two people in front.” Ah. Okay. I put my arm out and down. If I stretch a tiny bit, I can reach the singers two rows forward. I wonder if this is a Distraction I’ll get marked down for (‘Please address the problem of freakily long limbs on the fourth row’), or whether it can be put to use in some Mr Tickle-themed comedy moment.

NOT choreo, just a bit of fun in a warm-up. Spot the Distractions. Yup, that would be me

Sally’s cracking the whip. “LOOK AT ME LOOK AT ME LOOK AT ME KEEP LOOKING AT ME I DON’T CARE IF YOU FALL OFF THE RISERS DON’T TAKE YOUR EYES OFF ME.”

Jane, unperturbed, is adding new bits. “Right, do this, starting on the left. Hmm. Now do it the other way round. Okay, now do it the first way again.” She videos us. I immediately do absolutely everything wrong.

Now we’re going through a different song. YES. I’ve been practising this one at home. BRING IT ON. Right. All good so far. Yes, that’s right. Oh. That move. Oh yeah. Too late. Argh. Sally: “Don’t go on autopilot. NEVER go on autopilot.”

Yup. My mistakes come when I allow myself a nanosecond to think, “I got that RIGHT!” I spiral gloomily into meta-meta-meta-awareness, trying to stop myself worrying about trying to stop myself critiquing my own performance as I go along.

In the break, Karen must have noticed my air of abject terror. “It’ll come together. It always comes together.”

Back at home, I watch tonight’s video. In between absently thinking, “Gosh, I’m so ridiculously tall,” it hits me how Rachel is right when she says every single person matters. We’ve all got our homework to do, and our small but crucial contribution to make. And when we all get it right, it gathers you up and sweeps you along, and it’s completely thrilling to watch.

I run through it in my socks in the kitchen, cracking my head on a light fitting and knocking over a bottle of wine. But the final chord makes me well up every time. Blimey. This is going to be AWESOME.

‘It’s all about having fun!’ my teacher said. ‘Not pitch, or timing, or accuracy.’ Then, pointedly: ‘It would be really good for you.’

The previous week, I’d reclined on her figurative couch and rambled on about my musical upbringing, while she tried not to look too shocked. Apparently there’s more to making music than Getting It Right. Some people find it enjoyable! Who knew?

Despite my conviction that rabid anxiety is all that’s holding me together, she insists I need to loosen up. Enjoying singing, it turns out, is not just about hitting that high F on your own in the kitchen, to the freezer’s baritone thrum. It involves OTHER PEOPLE. So there I was in the Town Hall bar, waiting for the Women’s Community Singing Group to show up. Efficient types tried to recruit me to the Arts Festival volunteer posse. I may have agreed. I’m not sure what to.

I’ll admit I was PETRIFIED. There’s a whole lot of community in our town, and it mostly freaks me RIGHT out. While I’ll happily wave at people from the safety of the other side of the square, I feel like an alien interloper among all these people Gaily Mucking In.

There was no time to worry about the strange local customs, though, as we were OFF with the fiendish warmups. Hannah, looking in through the window, was appalled:

My kung fu background helped, here: I am no stranger to waving my limbs around and looking a bit daft in public. The verbal exercises were a different story. Try this. Count out loud, singing up and down the scale as you go. One. One two one. One two three two one*. Go up to five, then six, then seven. Quicker. Now replace every ‘three’ with a clap. Now do it in French. The teacher was laughing openly at me by the end.

Notation? Pah!

OK, first song. Four parts. I nipped round to join the basses. Wise decision, as it was an easy part with lots of repetition. It’s all taught by ear, so no music to read; instead, the teacher goes through each part in turn and you’re supposed to remember yours. Then you all sing together. I was smugly confident**, but it was more difficult than I expected, mostly because a) I realised halfway through that I was trying to remember everyone else’s parts as well as mine, and b) it was all in Swahili, FGS.

A cup of tea, and then a different song, with harder words. Happily, my section were mainly going, ‘Hum, bum, KULE!’ Well, I think we were. I’ve done some group singing before, but this was weirder than I remember. Maybe it was the room; I couldn’t hear myself, and I couldn’t really hear anyone else. Singing turned into a leap of faith. (I explained this to the boyf later; he said, darkly, ‘You can hear yourself if you’re doing it wrong.’) Every time I tried to listen to what everyone else was doing, I screwed my bit up. A couple of times, I was so busy watching for the cue I completely forgot to sing at all.

The next day, I tried to teach the boiz ‘Hum, bum, KULE!/ Sha-la, la, la!’ in three parts over breakfast. We got as far as the 6yo going, ‘Hum, BUM! You HUM. Out of your BUM!’ and the two of them collapsing. Boyf [horrified look]: ‘You were doing WORLD MUSIC?’

But it was fun. No, it really was. I had fun. Me, Little Miss Don’t­-Make-Me-Leave-The-House. The basses were a jolly bunch, cracking jokes and making up dance steps and coming in in the wrong places and cackling. People kept introducing themselves to me, even though I forgot all their names instantly out of shock. (I decided just to call everyone Sarah or Cathy.) It was bewilderingly friendly. ‘Are you new? Are you going to come again?’ Yes. And yes. ‘Good!’